Helical Pile Calculator, IBC 2021

What it checks

The module designs helical piles using manufacturer tabular bearing methods and torque correlations. It evaluates the pile's capacity under both strength and service limit states, applying the IBC 2021 deep-foundation requirements. The design process begins by calculating individual helix plate bearing capacities and summing them for total bearing capacity. Next, the module determines the ultimate capacity via the torque correlation method. It identifies the governing ultimate capacity as the minimum of the bearing and torque capacities. Finally, the module calculates the allowable capacity by dividing the governing ultimate capacity by the specified safety factor, providing a clear comparison against factored demands.

Inputs

Pile Geometry - Shaft designation (SS175, SS200, SS225, RS2875, RS3500), helix plate diameters (in), helix spacing (in), and depth to lead helix (ft).
Soil Properties - Ultimate soil bearing capacity at helix depth (ksf), effective soil friction angle (degrees), and optional soil unit weight (kcf).
Installation Data - Final installation torque (ft·lb) and the torque correlation factor Kt (ft^-1).
Load Demands - Factored compression demand (kips), factored tension demand (kips), and a flag to check compression only.
Design Parameters - ASD safety factor (typically 2.0-3.0).

What it reports

Individual Plate Capacity - The bearing capacity for each helix plate, calculated as area times bearing pressure (kips).
Total Bearing Capacity - The sum of all individual helix bearing capacities (kips).
Torque Correlation Capacity - The ultimate capacity derived from installation torque using the Kt factor (kips).
Governing Ultimate Capacity - The minimum of the total bearing capacity and the torque correlation capacity (kips).
Allowable Capacity - The governing ultimate capacity divided by the safety factor (kips).

Code references

The engine cites IBC 2021 §1810.3 for deep-foundation requirements. It utilizes the Hoyt & Clemence (1989) torque correlation where Q_ult = Kt × T. The module also applies Terzaghi-Meyerhof bearing factors for individual helix plates and references Chance, MacLean, and Ram Jack technical manuals for tabular capacities.

Limits

The module assumes a default soil unit weight when not supplied. If the compression-only flag is set, the module checks only compression and ignores tension. The module does not currently support other load combinations beyond the specified factored compression and tension demands. Results are engineering aids; the engineer of record is responsible for the design.

This module ships in the desktop app

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